The Study On Surface Oxidation Resistant Coating And High Temperature Performance

As for metals or alloys, a high temperature must be acquired to complete the heating processes. However, during the heating process, a thick layer of oxide scale will be formed at high temperature. So scaling is needed to remove the thick layer of oxide scale,but it not only cause the large loss, but also deteriorates the surface quality of final products and increase the subsequent removal cost. In recent decades developed the heat protection coating method,which has the advantages of low investment, simple operation,and the widely application range. Therefore, the heat protection coating method is the main way to solve too much oxidation loss in the heating process.In this paper, Q235 steel was studied. The article focused on preparation of oxidation resistance coating, explored the mechanism of oxidation of the coating, and characterized the surface morphology, organizational structure, chemical composition of oxide scale by Microscope, field emission scanning electron microscopy(FESEM), XRay Diffraction(XRD), and thermo-analytical instrument(TG/DSC).We prepared Na2 Si O3 coating by orthogonal experiments., and contrasted the weight changes before and after oxidation test. The results showed that the Na2 Si O3 coating maximum operating temperature is 1100℃, at this temperature for 120 min, can reduce the 84.25% oxidation loss.We prepared a kind of phosphate coating by aluminum tripolyphosphate modified aluminum phosphate. The results showed that the phosphate coating maximum operating temperature is 1300℃, at this temperature for 120 min, can reduce the 57.82% oxidation loss. The thickness of oxide scale of blank sample was 654 um, but the coated is 357 um,the structure of oxide scale can be divided into three layers: Fe O, Fe2O3 and Fe3O4; but the blank did not have layered structure, only contained Fe2O3 and Fe3O4, because it is fully reacted with oxygen.